Machine for grinding lenses.



W. H. JOHNSON. MACHINE FOR GRINDING LENSES.

- APPLICATION FILED JAN.Z8.1911. 1,001,410.

Patented Aug. 22, 1911 IIIIIIIXIII w I H. JOHNSON; MACHINE FOR GRINDINGLENSES. APPLIUATIORI'ILED JAN. 28, 1911.

Patented Aug. 22; 1911.

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WALTER H. JOHNSON, F EST 1 KBUlt'Z. MASSACHUEEUITS, ASSIGNOP. OFONE-HALL TO CHARLES T. SAUL, O11 W'ALTl-IAM, MASSACHUSETTS.

MACHINE FOR GRINDING LENSES.

To all whom it may concern:

Be known that 1 WAi'xrnn ll. donation, a citizen of the United Staten.residing a test Rortbury, in the county o t Hutlolk and State ofhilassaehusetts. have invented new and useful improvements inl\l-.iehines t'or GrindingLenses, of which the .t'ollowing aspecification. This invention relates to machines grinding lenses.

The olfect of the invention to provide for a machine which will grindany kind of cylinder lens, toric or plain. and which will grind theconvex or concave t'ares oi? lcnscs with very slight change in theparts.

The object of the machine is further to provide a machine which can beoperated quickly and easily by comparatively inc:- perieneed and cheapoperators.

in ju'iachines oil the character set l'orth it is very desirable thatthe grinding element should pass over the surface of the lens to heground in a variety of paths, none ot which are duplicates of eachother. To accomplish this result, the machine o'l' this invention is soconstructed and operated that. the grinding element which moves over thesurface (it the lens, or the lens itself when it is .n'iovtajl over thesurface oi the work holder. has an iinleterminatc movement. inn partedlll8l1tt)-llltlii is. said tlotttt'tlt n iovc d and in another directionat an angle to the in one direction. by one mechanism Specification ofLetters Patent.

.lirst by another mechanism, and these two:

n'wchanisms vary in their action relatively to each other, For thereason that one o1" them is driven by a slipping Frictional means, sothat the two mechanisms are constantly changing in their relative timesof movement and consequently the grinding element which is driven bythese mechanisms moves in a resultant path which constantly varies andwhich cannot be predetermined, or, in-other words, is indeterminate,because of the fact that one of these mechanisms is driven by a slippingfrictional means, and said means will slip according to the amount ofresistance encountered at certain times by the moving grindingelement.

The invention consists in the combination and arrangement of parts setforth in the following. specification and particularly pointed out inthe claims thereof.

Referring to' the drawings: Figure 1' is a plan View of my improved lensgrinding Patented Aug. 22, 19M.

Application filed January 28, 1911. Serial No. (305,157.

machine. Fig. ".3 a side elevation viewed in the dirw-tion ol' the arrown. Fig. l. and shown partly in section. l ig. it is a front elevationviewed from the right of l igis. l and illustrating the grimling membersand work holder arranged to grind the concave side ot a lens. l ig. -lis a plan View of the grinding members and work holder, with the guideFor preventing the gi'iiuling member t'roni rotating about its mediumaxial line in section. .l"ig. 5 is 'l'ront elevation viewed in the samedirection as Fig. 11. illustrating the naichine with the grind ingnu-inbrr adapted to grind the convex side oi a lens. the same beingshown partly in section. Fig. (3 is a front, elevation of a moditicdForm of means For preventing the movable grinding member from rotatingabout its median axial line. Fig. 7 is-a side elevation of the partsillustrated in Fig. (3 as viewed from the left of said Fig. (l.

Like numerals refer to like parts through out thr'scvcral views of thedrawings.

in the drawings, id is the frame of the machine and It the main drivingshaft journal d to rotate in a suitable bearing driving pulley i3 isfastened to the shaft- 2 and ionrnaled upon said shaft is a loose pulleyt 1. another pulley '15 is fastened to th sha it it and has projectingfrom its lace and hot thereto a cranlepin 16. The crankpin il isconnected by a crank-rod 17 to a slide it; by means of a pivotalconnecting bolt ll), said crank rod 17 is movable laterally thereof onthe crank pin it). The slide ,ltw' is guided in ways 20 Formed in aslide it which consists of a block 29 tastened to rods 23, 23. the rods23% being adapted to slide in hearings 94., 94- formed on the standardwhich is a part of the frame of the machine.

A, reciprta'atory motion is imparted to the slide 21 by a. cam 26loosely mounted to 1o tate upon the shaft. 11, and driven by a belt 27.This helt 537 is an endless belt and extends lrom the pulley 15 aroundidler guide pulleys 28, 30 and 31 and around the pulley 39 which is fastto the sum 26. To regulate the tension on the belt 27 the idler guidepulleys, via, the pulleys 3i and 29 are mounted upon a bracket which isadjustahly fastened by means of a bolt. 34 to the base 35 ol' the frame10. The reciprocat'ory motion is imparted to the slide 21 from the cam96 by acam lever 36 which is pivoted the other end thereofheingconnected by a pivotal stud 'l'O tothe block 22 which forms aportion of the slide 21, the whole of said slide consisting of the block22, the cap )late fast thereto and the uide rods- The slide 18 hasfastened to its front end a head 41. by means of a set-screw l2 and thishead has slidably mounted therein a rod which has a. collar 4st fastthereto, said collar having a handle 44: fast thereto by means of which.it may be raised. interposed between said collar and the head 41 is aspring which encircles the rod 43 and tends t-o'hold said roddowmvardly. The lower end of the rod 4-3 is rounded at 4:6 and fits intoa recess 47 in the grinding clement 4-8 (Fi 2).

By reference to Figs. 2 and it will be seen that there are two elements48 and 51 having opposed faces 53 and 52, respec tively one of saidelements 48 constituting a grinding element and the other element 51 awork holder. The element 51 is convex upon its grinding surface 52 andhas a lug 54c projecting downwardly therefrom into a recess 55 in theframe 10. Vt hen it is desired to grind the concave side of the lens 49,said. lens is interposed between the elements l8 and 51 and is fastenedto the element 418 by means of a suitable cement,

In order 'to prevent the element 4:8 from irotatine' about the medianaxial line of the rod 43, or about a median axial'line extendingsubstantially at right angles to the grinding surface of the element 51,a rod 56 is fastened to the grinding element 48 and projects therefromtoward th right (Fig. 3) into a slot 57 formed between the two K sides58, 58 of a bracket 59 which is bent at right angles at'its upper'endand is preferably formed of. wire, the bracket 59 being fastened to thehead 41 by a set screw 60. The rod 56 is extended to the left of thegrinding element 48, as illustrated in Fig. 3, in order to enable theoperator to conveniently and quickly lift the grinding element 48 awayfrom the element 51 when it is desired to remove the lens from betweenthe opposing faces of the ele ments 48 and 51 or to insert a new lenstherebetween. This extension of the rod 56 to the left, Fig. 3, is alsofor the purpose of enabling the operator to remove the grinding element48, with the lens attached thereto, and turn said grinding elementaround 180", thus reversing the positions of the right and left handends of the rod 56 and that portion which previously extended to theleft of the grinding element 48 will then extend to the right of saidgrinding element-and into the slot 57 in the bracket 59.

in F 2 and the lens is illustrated as fastened to the uppergrindingelement 48 and the convex grinding face 52 of the element 51 remainsstationary, While the lens moved around by the mechanism hereinbeforedescribed in the manner hereinafter more fully set forth. In Fig. 5,however, the grinding clement 1-8 is replaced by a grinding element 48'having a concave grind- A face 53' and the lens 49 is fastened by cement50 to the element 51', which is ren'iorably fastened to the frame of themachine by means of a lug 54 which projects into the recess The rod 43is'the same as in the form of my invention illustrated in Figs; 1 and 2;also the guiding bracket 59, and the element 48 are provided with rods56 and 56 which perform the same functions as the rod 56 in the form ofmy invention illustrated in Fig. 3.

in Fi and '7 I have illustrated a modified means for preventing the lensfrom rotating around an axis substantially at right angles to itssurface during the grindin operation, and referring to said Figs. 6 an 7it will be seen that the element 5]. is supported on the frame of themachine as in the forms of my invent-ionv illustrated in l i s. 2 and 5,While the grinding element -1-8, which, in this particular form has thelens l9 fast thereto, is pivota'lly mounted .to rock upon the roundedend of the rod 43, as hereinbefore described, the element 48 having cars61, 61 thereon which straddle ti -shaped rods 56, 56* which are fastenedto a collar 62 which, in turn, is fastened to the rod The generaloperation of the machine hereinbefore specifically described is as'follows. Considering, first, the-grinding of a lens on the concave facethereof and referring to Figs. 1, and 3, the operator attaches the lens49 to the grinding element 48 by means of suitable cement as illustratedin Figs 2 and 3, and utilizes for the other element the part 51'. Heplaces the part 5-1 in the position illustrated in Figs. 2 and 3 andcovers the same with a suitable grinding material, then. raises the rod43, by means of the handle 4-4, overcoming the action of the spring Hethen places the lens 49 attached to the grinding member 48 by the cement50, beneath the rod 43 and lowers said rod until the rounded lower end46 thereof enters the recess 4:? in the grinding He lowers the rod 43and the element element 48 with the lens attached thereto, manipulatingthe rod to this end by means of the handle 44 and the grinding element48 and lens by means of the handle or rod He then starts the machine byslipping the belt from the loose pulley 14 onto the tight pulley 13( Theshaft 11 is then rotatedand this imparts a reciprocatory motion to theslide 18 from the front; to the back' of the machine, while the cam 32bwill be rotated loosely upon the shaft; 16 by the belt. 27, and thiswill rock the cam lever 36 and.

through the link 38, the slide it. will he given a reciprocatvory motionat. an angle (in this case at, right angles) to the. direction of motionof the slide 18. The resultant motion imparted to the grinding clementto, due to the combined movements of the two slides 18 and it will movesaid grinding element in dilletrnt. directions around over the element51., thus grinding the concave surface of the lens 'll) which is incontact with the grinding material upon the convex surface 52 of saidelen'ient It is evident that the grinding element t9 and the lensattached thereto can tip in ditferent directions as it is moved aroundin a curvilinear path by the mechanism hereinbefore described. Thedistance, lic-iwever, to which said lens can be rocked about the medianaxial line of the rod 43 is limited by the rod 56 which projects intothe slot 57 between the two sides 58, 58 ot the bracket 59. This rod cantip upwardly and down wardly, but limits the angle to which the element48 can be rotated, together with the lens, about said median axial line.

It will be understood that the belt 27 is loose enough so that it acertain amount of resistance to the movement of the grinding element 48and the lens attached thereto is encountered said belt will slip uponthe pul leys and, therefore, the relative location of the cam 26 to thebelt- 15 and to the crank pin 16 fast thereto will be changed and assoon as this occurs the path which the element stSwould otherwise havedescrilaid will be changed. This change occurs according to the amountof resistance and the number of dill'erent times that a certain excessot resistance, so to speak. occurs-during the grinding operation and,thcrc'tore, the resultant path imparted to the grinding element 48 andthe lens attached thereto is indeterminate, and also it will beumlerstood that because of this slipping connection between the pulleys'15 and 32, the movcnwnt il'nparted to the grinding element isindeterminate movement, and, further that one of said elements, vim, inthis embodiment ol my invention, the element 1-8, will be moved in aplurality of directions at an angle to each other relatively to theelement 51.

It will be noted that the handle -l-l; has screw-threaded engagementwith the collar 4i and, tln-u'e'fore. acts as a set-screw to l'asten thecollar 44 to the rod 43. It it is, desired. therefore, to increase ordiminish the tension upon the spring 45. it can be done by loosening theset'screw handle ll and moving the collar 4 t upwardly or downwardly,respectively, according as it is desired to inijzrease or diminish thetension upon the spring This. of course. results in increasing ordiminishing the pressure of the lens against the grinding snrl'ace.

When it is desired to grind a convex surface on a lens, the partsillustrated in Fig. I)

are utilized. in this case the under side of the element to is madeconcave and the lens ll is fastened to the element a which may tune aconvex upper sin-lace or not. as desired. The mechanism is the same asthat i|lu.--;tratcd in Figs. l. .2 and 33 and in the operation of themachine in this embodiment of my invention the lens remains stationary.while the element 41'1" slides around upon its convex surl'acc. therebeing introduced between the grinding element 18' and the upper convexsurface ol the lens, suitable grinding material.

in Figs. 13 and T the grinding element i8 is provided with cars whichengage the U- shaped rods 56 and all, and thus said rods 56 and 5(3allow the grinding element in to rock, together with the lens. as it ismoved around upon the convex surface of the part 51". but do not allowsaid grinding clement l8 to rotate about the axis of the rod 423. Inthis embodiment of my invention. the othcr parts of the machine are thesame as illus trated in Figs. l, '2 and 2Shereinbel'ore described.

, Having thus described myinvention, what l claim and desire by LettersPatent to secure, is:

l. A machine for grinding lenses having, in combination, two elementshaving opposcd surlaces one of said elements constituting a work holderand the otlu a grimling element. two slides. one mounted on the other,said slides adapted to s' dc re. 'ieclivcly at an angle to each other.one of said elements pivotally connected to one of said slides. acrank-pin, a crank rod com'iecting said crank-pin to one ol said slidesand movable latcrally thereof on said crank-pin. a. cam. and mechanismoperativcly connecting said cam to the other of said slides, and means'l'orming a slipping frictional conncction between said crank-pin andcam.

J. machine for grinding lenses having, in combination. two elementshavingopposed snrl'aces one of said elements constituting a work holderand the other a grinding element. two :lidcs. one mounted on the other.said slides adapted to slide respectively at an angle to each other. oneof said elements pivotally connected to one ol said slides. a. pulley, acrank-pin fast thereto. a crank-rod connecting said crank-pin to one ofsaid slides and mo\ able laterally thereof on said crank pin, a cam andmechanism operalively onnecting said cam to thi other ot said slides. a.pulley fast to said cam, and an eudless belt connecting said pulleys andadapted to slip thereon.

3. A machine for grinding lenseshaving, in combination, two elementshaving opposed surfaces one'of said elements constituting a Work holderand the other a grind ing element, two slides, one mounted on the other,said slides adapted to slide respectively at an angle to each other, oneof said elements pivotally connected to one of said slides, a pulley, acrank-pin fast thereto, a crank-rod eonnecting'said crank-pin to one ofsaid slides and movable laterally thereof on said crank-pin, a cam,mechanism operati'vely connecting said cam to the other of said slides,a pulley fast to said cam, an endless beltconnecting said-pulleys andadapted to slip thereo11,.and means to adjust the tension on said belt.

4. Armachine for grinding lenses having, in combination, two elementshaving opposed surfaces one of said elements constituting a work holderand the other a grinding element, two slides, one mounted on theother,said slides'adapted to slide respectively at an angle to each other, oneofsaid elements pivotally connected to one of said slides, a pulley, acrank-pin fast thereto, a

to guide said belt, one of said idler pulleysv being adjustable, wherebythe tension on said belt may be varied and said belt allowed to slip.

In testimony whereof I have hereunto set my hand in presence of twosubscribing Witnesses.

WALTER H. JOHNSON.

' Witnesses:

CHARLES S. GOODING, Louis A. Jones.

